Blast feed device for a steel converter

ABSTRACT

This device for supplying wind to be blown through the bottom of a steel converter, adapted to ensure a double yet separate feed to the blast tuyeres and wherein said tuyeres comprise for each blowhole a pair of concentric metal tubes adapted to be supplied with different gaseous substances, such as a combustive agent, for instance pure oxygen, and a cooling gas such as water steam or carbon dioxide gas, said device comprising essentially a body constituting a two-compartment chamber, each compartment being adapted to supply a specific substance annularly to at least one injector having its head engaged in a fluidtight manner against the base of the particular one of the pair of tubes of each tuyeres which it is intended to supply with this gaseous substance.

United States Eatent Inventors Marcel Gombert Mietz-Queuleu; PierreLeroy, St. Germain en Laye; Emile Sprunclr, Moyeuvre-Grande, all ofFrance Appl. No. 5,303

Filed Jan. 23, 1970 Patented Sept. 28, 1971 Assignee Wendel-Sidelor andCompagnie des Ateliers et Forges de la Loire (St- Charmand, Firming,St-Etienne, Jacob liloltzer) Priority Jan. 28, 1969, Nov. 6, 1969 France6,901,640 and 6,938,151

BLAST FEED DEVICE FOR A STEEL CONVERTER 14 Claims, 6 Drawing Figs.

ll.S. Cl 266/34 T,

266/41 Int. Cl (1211c 7/00 Field 01 Search 266/41, 35,

36 P, 34 L, 34 T; 122/66; 110/1825 [56} Eeierences Cited UNITED STATESPATENTS 2,562,813 7/1951 Ogorzaly et al 266/35 3,397,878 8/1968 Holmeset a1. 266/41 Primary Examiner-Gerald A. Dost Att0rney-Wenderoth, Lind &Ponack ABSTRACT: This device for supplying wind to be blown through thebottom of a steel converter, adapted to ensure a double yet separatefeed to the blast twyeres and wherein said tuyeres comprise for eachblowhole a pair of concentric metal tubes adapted to be supplied withdifferent gaseous substances, such as a combustive agent, for instancepure oxygen, and a cooling gas such as water steam or carbon dioxide gassaid device comprising essentially a body constituting a twocompartmentchamber, each compartment being adapted to supply a specific substanceannularly to at least one injector having its head engaged in afluidtight manner against the base of the particular one of the pairoftubes of each tuyeres which it is intended to supply with this gaseoussubstance.

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sum [1F 5 INVENTORS MARCEL GOMBERT PIERRE LEROY EMILE SPRUNCK ATTORNEYSBLAST FEED DEVICE FOR A STEEL CONVERTER In a prior Pat. application Ser.No. 739,553 filed June 24, 1968 by Pierre Leroy, there is described adevice for supplying wind to be blown through the bottom of a steelconverter, which is particularly advantageous when the blast pressureexceeds 3 bars or 43 p.s.i. This device comprises a plurality of headertubes under pressure having either the shape of concentric tores or anyother suitable configuration, each header being adapted to supply blastwind to a number of blast pipe or blowholes disposed in the bottom ofthe converter.

ln aforesaid prior patent application there are provided, for connectingeach header to the blasthole proper, either flexible hoses, orsmall-diameter tubes forming one or more turns in order to impart acertain elasticity thereto, either device being advantageously providedwith self-sealing unions.

Each blasthole or pipe consisting of a metal tube is supplied with blastwind through a movable injector engaging in a fluidtight manner, withits head, the frustoconical base of the metal tube, this injector beingfed in turn from a blowing box or like chamber under pressurecommunicating therewith. If desired, this injector may be provided witha movable valve member, the injector axis and the valve axis being bothcoincident with the axis of the pipe or like means constituting theblowpipe or hole.

In case a relatively great number of such blast pipes are provided,these are relatively close to each other and the devices for connectingthem to the above-mentioned headers become cumbersome. Therefore, insaid former patent application a device is provided which ischaracterized in that each header under pressure is mounted directly tothe baseplate, against a row of blowholes, and that a movable injector,with or without valve or sealing member, extends therethrough, theinjector axis and possibly the axis of the valve or sealing member beingcoincident with the axis of the metal tube constituting the relevantblowhole.

ln the devices described and illustrated in said patent application andof which the essential features are briefly summarized in the foregoing,the bottom of the steel converter is supplied with blow wind consistingof a single gas, either pure or in admixture.

Now it may be necessary for certain processes, to blow simultaneouslytwo different gases through a common tuyere, the latter comprising adouble feed system so designed that it is possible to blow on the onehand along the axis of said tuyere pure oxygen or oxygen-enriched air,or any other suitable gaseous combustive agent, and on the other hand,along the outer periphery of said oxygen jet, a cooling gas such aswater steam or carbon dioxide gas.

It is the essential object of the present invention to permit a generalapplication of the devices described and illustrated in the aforesaidprior patent application (originally designed for a single-feed system)to a double-feed system, so that two gases not mixed beforehand can beblown simultaneously under pressures in excess of 3 bars (43 p.s.i.)i.e. the value constituting the maximum blowing pressures in Bessemerand Thomas steelmaking processes, so that blowing pressures of the orderof 20 bars (290 p.s.i.) or more can be used.

To this end, the present invention is concerned primarily with anarrangement permitting the double and separate feed of blowing tuyeresprovided at the bottom of a steel converter with two different gases,wherein said tuyeres comprise in each blowhole a pair of concentricmetal tubes, this device being characterized in that it consists of achamber comprising two separate compartments each adapted to supply in aradial direction at least one injector engaging in a fluidtight manner,

with its head, the base of the specific tube of each tuyere to besupplied with this gas.

It is another object of the present invention to provide different formsof embodiment of this device, the first form of embodiment beingapplicable to a limited number of tuyeres, the second form of embodimentbeing applicable preferably to a greater number of tuyeres.

In the first form of embodiment, each tuyeres comprises its separate,preferably cylindrical, two-compartment feed chamber, and eachcompartment is connected to the relevant gas header through a flexiblehose or tube of relatively small diameter. Under these conditions, thenumber of flexible hoses or tubes is twice that of the tuyeres.

in the other form of embodiment, each row of tuyeres comprises aseparate two-compartment feed chamber, preferably of toroidalconfiguration, receiving therethrough, in alignment with each tuyere, apair of injectors each connected to a separate compartment, each one ofthe pair of toroidal compartments being fed at one or a plurality ofcircumferentially spaced points through any suitable means,small-diameter pipe or flexible hose.

In each one of these forms of embodiment the lowermost injector of eachtuyere feeding the central tube may be provided with a valve member ofthe type already described in the aforesaid patent application, andadapted to be used when it is desired to measure the degree of wear ofthe tuyere in actual service, for example for detecting an abnormallyhigh rate of wear in comparison with the rate of wear of the othertuyeres.

However, it is also possible to dispense with this valve member and inthis case the measurement of the rate of wear of a tuyere and theputting of this tuyere out of service are effected by unscrewing a screwplug at the base of the central injector and introducing into thecentrall tube of the tuyere involved a solid rod, or alternately byclogging this tube with a suitable pulverulent product.

After exhaustive tests the applicants found that in actual service,during a refining process consisting in converting cast iron into steel,the outer tube of each tuyere was stressed mainly in the longitudinaldirection, this causing movements of the order of several centimetersdirected mostly towards the inside of the converter. If the outer tubeis secured in a rigid manner, considerable strain may result, which maycause tearing, stripping, torsions, etc. resulting in detrimental anddangerous leakages.

The true reasons of these longitudinal efforts exerted against theexternal tube of each tuyere have not been clearly identified so far. Itappears that they are ascribable to complex reasons including thefollowing phenomena:

inherent distorsions of the refractory bottom, consisting chiefly oftarred dolomites;

development of a protrusion of solidified metal of variable magnitude,at the inner end of the external tube, which is pushed by the windpressure exerted against this protrusion;

convection movements of the liquid bath around the tuyeres due to theimpulse of the gaseous jet issuing therefrom, with due consideration forthe aforesaid protrusion of solidified metal.

Whatever the real causes of these longitudinal stresses, the solutionfor avoiding their detrimental tearing and breaking action on theexternal tube consists in removing any rigidity from the mounting of theassembly comprising each two-compartment chamber and the correspondingtubes.

Consequently, this invention is also concerned with the provision of adevice for supplying blow wind to the bottom of a refining converter,said device being arranged with a view to ensure a double yet separatesupply of gaseous substances to blowing tuyeres comprising twoconcentric tubes, which device consists of a chamber comprising twoseparate compartments each adapted to feed annularly at least oneinjector of which the head engages on the one hand, in a fluidtight andrigid manner, the base of the tube of each tuyere which is fed thereby,said device being characterized in that said two-compartment chamberrigid with the two tubes of the tuyere is adapted to slide within aguide sheath rigidly secured to the bottom plate of the converter, thefront face of said chamber bearing against a suitable resilient memberfitted against and/or into the bottom plate, the rear face of saidchamber abutting on the other hand against any suitable locking means,such as one or a pair of transverse pins.

According to a specific feature characterizing this invention saidresilient member consists of one or a plurality of springs, or a set ofdished spring washers, or the like.

As will be readily understood, this last-mentioned improvement consistsin imparting a certain longitudinal flexibility to the assemblycomprising the pair of coaxial tubes and their two-compartment feedchamber. Since in most instances the external tube is urged towards theinside of the converter, the resilient member such as a coil compressionspring or a set of dished spring washers or other suitable means isdisposed between the front face of each chamber and the bottom plate ofthe converter. On the opposite end, i.e. adjacent the rear face, someresilient means may also be provided, if desired, but in most instancesit would prove useless. From this side, for safety reasons, a lockingsystem may be introduced which consists simply of one or a pair oftransverse lock pins constituting abutment members in the outwarddirection, thus preventing the movable system from being accidentallyexpelled or ejected from its receiving cavity.

Other features and advantages characterizing this invention will appearas the following description proceeds with reference to the attacheddrawing illustrating diagrammatically be way of example a plurality offorms of embodiment. In the drawing:

FIG. 1 illustrates in axial section a device according to thisinvention, the section being taken along the axis of a blowing tuyere;however, this section is a meridian section of the cylindrical device inthe case of the first form of embodiment broadly set forth hereinabove,and a transverse or cross section of the toroidal device in the case ofthe other form of embodiment, as will be explained hereinafter;

FIG. 2 illustrates a meridian section of a third form of embodiment;

FIG. 3 is a cross section of this third form of embodiment;

FIG. 4 is a view similar to FIG. 1 illustrating a modified construction;

FIG. 5 is a view similar to FIG. 2 wherein a different type of springconstruction is used; and

FIG. 6 is a plan view illustrating a toroidal construction wherein sixheaders supply the blast air and the communication ducts associatedtherewith.

Referring ot FIG. 1, the reference numeral 2 designates the bottom platesupporting the bottom 1 of the converter, of refractory material. Thisbottom plate 2 has formed therethrough an orifice 3 in which a sleevedesignated in general by the reference numeral 4 is fitted. This sleeve4 comprises an axial bore 5 and a plurality of channels such as 6, thefunction of which will be explained presently.

The concentric metal tubes 7 and 8 constituting the tuyeres proper arepositioned in said axial bore 5 of sleeve 4. In the example illustrated,coppertubes are used to this end, the central tube having an innerdiameter of l2 mm. (0.47 inch) and an outer diameter of l4 mm. (0.55inch), and tube 8 has an inner diameter of 20 mm. (0.787 inch) and anouter diameter of 22 mm. (0.865 inch). In the central tube 7 having alength slightly greater than that of tube 8, a suitable gas such as pureoxygen is blown, and the outer tube 8 or more exactly the annular spaceformed between these tubes 7 and 8 receives a gaseous coolant. Bothtubes 7 and 8 are formed with frustoconical outer ends shown at 9 and10, respectively.

The sleeve 4 has welded to its underface 37 a body designated in generalby the reference numeral 11 which constitutes a chamber divided into twocompartments 12 and 13 respectively. Compartment 12 is fed withcombustive gas (pure oxygen, for instance) through an inlet 14, andcompartment 13 is fed with a gaseous coolant (such as water steam)through another inlet 15.

The concentric tubes 7 and 8 are fed through injectors 28 and 16,respectively.

The injector 16 of gaseous coolant has a bottom opening comprising insuccession firstly a screw-threaded cylindrical portion 17, then a plainfrustoconical portion 18 and finally a plain cylindrical portion 19,this opening being adapted to receive the central tube 7 with itsfrustoconical base 9 engaging the corresponding portion 18, and also thesecond injector 28 having its head screwed in the first portion 17.

On its outer lower face the injector 16 comprises a shoulder 20 engagingone or a plurality of rubber seals such as 21 fitted in annular groovesformed in the inner wall of body 11. The head of injector 16 comprisesalong its axis an aperture 22 having a greater diameter than tube 7 soas to permit the passage of cooling gas between injector l6 and tube 7,and thus introduce this gas into the annular space between the tubes 7and 8. (In the example illustrated the diameter of opening 22 is 18 mm.(0.7 inch).

The outer face of the head portion of injector 16 comprises a roundedportion 23 bearing against the frustoconical base 10 of tube 8, and alsoa flat shoulder 24 engaging the sleeve 4.

The injector 16 further comprises a plurality of radial openings such as25 through which the gaseous coolant delivered to compartment 13 viainlet 15 is introduced into the injector proper and thence between thetubes 7 and 8. This injector 16 is screwed to the body 11 by means ofthreads 26 when its lower portion 27 is rotated until the shoulder 24abuts against the sleeve 4; simultaneously, the rounded portion 23clamps without any excessive tightening force the frustoconical baseportion 10 of tube 8 against the sleeve 4.

The injector 28 of gaseous combustion agent comprises a plurality ofradial openings such as 29 through which this gaseous agent delivered tocompartment 12 via inlet 14 is introduced into this injector and thencethrough an axial aperture 30 into the central tube 7. This axialaperture 30 has the same diameter as tube 7, i.e. 12 mm. (0.47 inch) inthe exam ple illustrated.

The outer face of the head of injector 28 comprises, like the outer faceof the head of injector 16, a rounded portion 31 bearing against thefrustoconical base portion 9 of tube 7, and a flat shoulder 32 engagingthe base of the frustoconical contour 18 of injector 16. The fluidtightness between injector 28 and body 11 is obtained by means of one ora plurality of rubber seals such as 33. The base of injector 28 isnormally sealed by a screw plug 34 adapted to be unscrewed in case ofneed by rotating its hexagonal head 35.

This injector 28 is screwed in the tapped contour 17 of injector 16 whenits lower portion 36 is rotated until the shoulder 32 abuts against thebase of the frustoconical contour 18 of injector 16, and the roundedportion 31 clamps without any excessive force the frustoconical baseportion 9 of the tube 7 against the contour 18 of injector 16.

In a first form of embodiment of the device according to this invention,which comprises a relatively small, number of tuyeres, say less than 40,each tuyere incorporates its inherent device providing the double butseparate gas supply, in the form of a substantially cylindrical chamberof which the figure shows in this case a meridian section. For eachtuyere the inlets 14 and 15 are connected to one or a plurality ofoxygenfeed headers and to one or a plurality of cooling-gas feedheaders, by means of flexible hoses. The oxygen and coolinggas headers(not shown in FIG. 1) are secured to the converter and themselvesadapted to be supplied at one or several points either through a rigidduct extending through the hollow trunnion of the converter or through alarge flexible hose. These two headers may advantageously have atoroidal configuration.

If a greater number of tuyeres is contemplated, the number of flexiblehoses would obviously become prohibitive. Therefore, in this case amodified or second form of embodiment may advantageously be used whereina double but separate feed system consisting of a chamber of toroidalconfiguration, of which the cross-sectional illustration is shown inFIG. 1, is disposed beneath each row of tuyeres, with the onlydifference that the sleeve 4 is dispensed with and that the annular body11 is welded directly to the bottom plate 2, the base 10 of tube 8 beingclamped between the rounded head 23 of injector 16 and a frustoconicalcontour machined in the baseplate 2 (not shown in the FIG.). Under theseconditions, the number of annular chambers or bodies 11 corresponds tothe number of rows of tuyeres in the converter bottom. Each annular body11 may thus comprise one or a plurality of pairs of inlets 14,

connected through flexible hoses or rigid tubes to the supply ductsdelivering on the one hand pure oxygen and on the other hand a gaseouscoolant. However, in this second form of embodiment each tuyere is stillcomprised of a first injector 16 and a second injector 28 both ofrevolution about the axis of the corresponding tuyere, as in the firstform of embodiment. Only the body 11 which was of cylindricalconfiguration about the tuyere axis in the first form of embodiment isnow toroidal about the axis of the converter bottom, in the second formof embodiment.

In either forms of embodiment any leakage of oxygen to the outside ispositively prevented by the rubber seal 33. Any communication betweencompartments 12 and 13 is prevented by the rubber seal or ring 21.Finally, any possible gaseous leak between the base 10 of outer tube 8and sleeve l would be exhausted via the leakage ducts 6 provided in thissleeve 4 and could therefore not seep to the bottom of the converter. Inthe second form of embodiment, the sleeve 4! is dispensed with asalready explained hereinabove and the leakage duct 6 are fonned in thebottom plate 2 proper, and open of course to the outside, under thebottom plate, as already explained in the above-mentioned prior patentapplication.

Now reference will be made to FIGS. 2 and 3 of the drawing whichillustrate a third form of embodiment of the present invention. in thebottom plate 100 of the converter a member 102 is secured by screwing;this member 102 comprises on the one hand a socket 103 formed with acylindrical bore and tightly fitted into the plate 100, and on the otherhand a guide portion consisting of a cylindrical skirt 1M formed withexpansion slots 105; this skirt 104 is open at its end opposite to thebottom plate 188.

Slidably mounted in this guide skirt MM is a unit comprised of the pairof tubes 1% and 107, and the member 108 providing a two-compartmentchamber 109, 110 enclosing the injectors 111 and 112, these injectorsengaging in a fluidtight manner, with their heads, the bases 113, and1M, respectively, of tubes W6 and 107.

The oxydizing gas, for example pure oxygen, is fed through an aperture115 into the chamber 109 via a flexible hose (not shown). The gaseouscoolant, such as water steam, is fed into chamber 110 via an opening 116and the supply is through another flexible hose (also not shown).

Between the front face 117 of member 108 and the inner bottom 118 ofmember 102 is a coil compression spring 119 or any other suitableresilient means reacting against the bottom 1 18.

On the other side of member 108 the ports 120 formed in said guide skirt104- permit the passage of a pair of transverse lock pins (not sown)extending through the drain plug 121 so as to avoid any interferencewith the necessary disassembling operations.

Finally, inside the member 108 toroidal seals 122 provide the necessaryfluid tightness at the proper locations.

The spring 119 is so calculated and constructed that in the absence ofany tractive effort exerted in the upward direction on the outer tube107, as seen in the FlGURE, the member 108 constituting thetwo-compartment chamber abuts against the pair of lock pins withoutexerting any pressure thereon outside the one resulting from itsinherent weight, whether the spring is fully expanded in this positionand the maximum tractive effort exerted in the upward direction as seenin the FIGURE and to which the tube 107 is normally subjected isinferior to the force necessary for compressing the spring 119 homeagainst the bottom 118.

Thus, the movable assembly has all the desired flexibility forpreventing any tearing off or rupture of tube 107.

in the construction of MG. 41 the sleeve 4 has been eliminated and theannular body llll is welded directly to the bottom plate 2. The base 10of the tube 8 is clamped between the rounded head 23 of the injector 1dand a frustoconical contour machined in the baseplate 2.

FIG. 5 is similar to FIG. 2 with the exception that the spring 119 hasbeen changed to the Belleville-type springs 119'.

The form of embodiment of FIG. 6 comprises six headers disposed eachbeneath one of the six rows of blastholes of the converter bottom.

The communication between the headers and the blastholes is obtained bymeans of one nozzle or injectors per hole, each nozzle or injector beingprovided with a valve member.

FIG. 6 illustrates six toroidal headers 21', 22', 23, 2d, 25' and 26'corresponding to the six rows of blastholes. The header 21' correspondsto the peripheral row, and is secured to the baseplate 2.

These headers are interconnected by four communication ducts 27, 28',29' and 30 of which the cross-sectional passage area decreases towardsthe center, according to a law ensuring a uniform distribution of theblast through the complete set of blastholes.

The blast wind under pressure is supplied to the device through theinlet 31 The blast inlet duct 31 is welded both to the plate 2supporting the bottom of the converter (not shown) and to the peripheralheader 21. The blast penetrates both into the peripheral header 21' andinto the communication duct 27 lt penetrates through these two pathsinto the complete device consisting of the six headers and the fourcommunication ducts.

Of course, it would not constitute a departure from the basic principlesof this invention to bring various modifications and detail improvementsin the practical embodiment of this invention, and even to contemplatethe use of equivalent means.

Besides, this invention is applicable not only to the bottoms ofrefining converters such as steelwork converters but also to any otherapparatus comprising a double yet separate feed, such as reactors,condensers, heat transfer apparatus, burners, etc. wherein a certainflexibility of the tubes is required for reasons specific to the casecontemplated.

What is claimed is:

1. A device for supplying wind to be blown through the bottom of a steelconverter, adapted to ensure a double yet separate feed to the blasttuyeres and wherein said tuyeres comprise for each blowhole a pair ofconcentric metal tubes, said device consisting of a body constituting atwo-compartment chamber wherein each compartment is adapted to supply agaseous substance annularly to at least one injector having its headengaged in a fluidtight manner against the base of the particular one ofthe pair of tubes of each tuyere which it is intended to supply with onegaseous substance.

2. A device as set forth in claim 1, wherein each tuyere comprises aseparate feed chamber having two compartments, said chamber beingpreferably cylindrical, each compartment of said chamber being connectedto the corresponding gas header through a flexible hose or asmall-diameter tube.

3. A device as set forth in claim 1., wherein each row of tuyerescomprises a separate feed chamber having two compartments, said chamberbeing preferably of toroidal configuration and receiving therethrough,registering with each tuyere, the pair of injectors each connected to aseparate compartment, and each one of said compartments is supplied withgaseous substance at one or a plurality of points of its circumferencethrough any suitable means such as a flexible hose or a small diametertube.

3. A device as set forth in claim 3, wherein the injector of each tuyerewhich feeds the central tube is closed at its base by a screw plugadapted to be unscrewed in case of need.

5. A device as set forth in claim 1, wherein the base of the tubes ofsaid tuyeres has a fnrstoconical portion adapted to coact with afrustoconical portion provided on each one of the corresponding injectorheads.

6. A device as set forth in claim 5, characterized in that the base ofthe tubes of said tuyeres is frustoconical and adapted to coact with acorresponding frustoconical portion provided on each one of the heads ofthe corresponding injectors for en suring the necessary fluidtightness.

7. A device as set forth in claim 2, wherein said two-compartmentchamber is welded to a sleeve inserted into a hold formed through thebottom plate of the converter.

8. A device as set forth in claim 7, wherein said sleeve comprises oneor a plurality of ducts opening into the surrounding atmosphere andacting as leakage ducts.

9. A device as set forth in claim 3, characterized in that said chamberis welded directly to the underface of the bottom plate of the converterwhich is provided with leakage ducts opening to the outside beneath saidbottom plate.

10. A device as set forth in claim 1, wherein said two-compartmentchamber rigid with the pair of tubes of the tuyeres is adapted to slidein a guiding cylindrical skirt rigidly secured to the bottom plate ofthe converter, the front face of said chamber bearing against aresilient member reacting against and/or into said bottom plate, itsrear face being adapted to react against a locking system.

11. A device as set forth in claim 10, wherein said resilient memberconsists of spring means.

12. A device as set forth in claim 10, wherein said resilient memberconsists of a set of dished spring washers.

13. A device as set forth in claim 10, wherein said locking systemconsists of one or a plurality of transverse lockpins extending throughslots formed in said guide skirt.

14. A device as set forth in claim 10, wherein said resilient member isso arranged that, in the absence of any tractive effort exerted on theexternal tube in the direction of the bottom of said converter, saidtwo-compartment chamber abuts against said locking system, without anyother pressure than that resulting from its inherent weight, saidresilient member being expanded completely in said position and themaximum tractive effort exerted in the direction of the bottom of saidconverter and to which the outer tube is normally subjected is inferiorto the effort necessary for compressing home said resilient memberagainst the bottom of the converter.

2. A device as set forth in claim 1, wherein each tuyere comprises aseparate feed chamber having two compartments, said chamber beingpreferably cylindrical, each compartment of said chamber being connectedto the corresponding gas header through a flexible hose or asmall-diameter tube.
 3. A device as set forth in claim 1, wherein eachrow of tuyeres comprises a separate feed chamber having twocompartments, said chamber being preferably of toroidal configurationand receiving therethrough, registering with each tuyere, the pair ofinjectors each connected to a separate compartment, and each one of saidcompartments is supplied with gaseous substance at one or a plurality ofpoints of its circumference through any suitable means such as aflexible hose or a small diameter tube.
 4. A device as set forth inclaim 3, wherein the injector of each tuyere which feeds the centraltube is closed at its base by a screw plug adapted to be unscrewed incase of need.
 5. A device as set forth in claim 1, wherein the base ofthe tubes of said tuyeres has a frustoconical portion adapted to coactwith a frustoconical portion provided on each one of the correspondinginjector heads.
 6. A device as set forth in claim 5, characterized inthat the base of the tubes of said tuyeres is frustoconical and adaptedto coact with a corresponding frustoconical portion provided on each oneof the heads of the corresponding injectors for ensuring the necessaryfluidtightness.
 7. A device as set forth in claim 2, wherein saidtwo-compartment chamber is welded to a sleeve inserted into a holeformed through the bottom plate of the converter.
 8. A device as setforth in claim 7, wherein said sleeve comprises one or a plurality ofducts opening into the surrounding atmosphere and acting as leakageducts.
 9. A device as set forth in claim 3, characterized in that saidchamber is welded directly to the underface of the bottom plate of theconverter which is provided with leakage ducts opening to the outsidebeneath said bottom plate.
 10. A device as set forth in claim 1, whereinsaid two-compartment chamber rigid with the pair of tube of the tuyeresis adapted to slide in a guiding cylindrical skirt rigidly secured tothe bottom plate of the converter, the front face of said chamberbearing against a resilient member reacting against and/or into saidbottom plate, its rear face being adapted to react against a lockingsystem.
 11. A device as set forth in claim 10, wherein said resilientmember consists of spring means.
 12. A device as set forth in claim 10,wherein said resilient member consists of a set of dished springwashers.
 13. A device as set forth in claim 10, wherein said lockingsystem consists of one or a plurality of transverse lockpins extendingthrough slots formed in said guide skirt.
 14. A device as set forth inclaim 10, wherein said resilient member is so arranged that, in theabsence of any tractive effort exerteD on the external tube in thedirection of the bottom of said converter, said two-compartment chamberabuts against said locking system, without any other pressure than thatresulting from its inherent weight, said resilient member being expandedcompletely in said position and the maximum tractive effort exerted inthe direction of the bottom of said converter and to which the outertube is normally subjected is inferior to the effort necessary forcompressing home said resilient member against the bottom of theconverter.